SAN LUIS OBISPO, Calif. (AP/CBS13) — A judge has denied a prosecutor’s bid to file rape charges against Paul Flores, the man accused of killing Cal Poly student Kristin Smart, who went missing 25 years ago.

The San Luis Obispo district attorney’s office had sought to add two rape charges — for offenses they say were committed in Los Angeles County after Smart, of Stockton, disappeared — to the complaint filed against Paul Flores in Smart’s death.

READ MORE: Gold Artifacts Stolen In Sacramento History Museum Break-in

Prosecutors on Wednesday revealed they found video of an alleged LA County rape, but a judge refused to add sexual assault charges saying evidence of an assault in the Smart case was too weak.

The judge ruled against the DA’s motion and scheduled a preliminary hearing in the murder case for Aug. 2.

READ MORE: 44 Structures Now Destroyed As Dixie Fire Grows To 240,795 Acres

Paul Flores, now 44, was the last person seen with Smart on May 25, 1996, at California Polytechnic State University in San Luis Obispo, where they were both freshmen. Prosecutors said he killed Smart while trying to rape her in his dorm room after he had agreed to walk her home from a party, where she had gotten intoxicated.

Her body has never been found.

Paul Flores’ father, Ruben Flores, has pleaded not guilty to accessory after murder in Smart’s death. The father and son were arrested in April after investigators at the San Luis Obispo County Sheriff’s Department found “biological evidence” indicating Smart was once buried under Ruben Flores’ deck behind his home in Arroyo Grande.

MORE NEWS: Search Continues For Woman Missing Following Boating Accident

Attorneys for the Floreses have denied that their clients committed any wrongdoing. A lawyer for Paul Flores on Wednesday called the prosecution’s attempt to add the rape charges a “publicity stunt,” according to KEYT.